Different structures of Oxide Thin Film Transistors (TFTs) have different properties. The electrical properties of the different structures need to be adjusted in a process design. There may be various complicated reaction mechanisms (e.g., electron transfer rate, ohm contact) between heterogeneous interfaces of the different structures. Therefore, the factors, such as process environment, plasma treatment, pollution treatment and light-shielding for an oxide semiconductor under illumination, become very important.
Zinc oxynitride (ZnON) TFT is preferred in the research and development due to a higher electron transfer rate and a lower price thereof. Compared with other oxide materials such as Indium Gallium Zinc Oxide (IGZO) material, the ZnON TFT generally has a bottom-gate structure.
Although the ZnON TFT is preferred in the research and development, a subthreshold swing (SS) performance of a TFT element is poor since the adding of nitrogen is an aporia in a ZnO type semiconductor material development and the ohm contact may become poor due to a drain of nitrogen.
There is not an effective solution in the related art to solve the above issue.